Abstract: A semiconductor laser device which has a diffraction grating partially provided in the vicinity of an active layer formed between a radiation-side reflection film provided on a radiation-side end surface of a laser beam and a reflection film provided on a reflection-side end surface of the laser beam, and which outputs a laser beam having a desired oscillation longitudinal mode based on a wavelength selection characteristic of at least the diffraction grating. The diffraction grating is formed in isolation with an isolation distance of Ls=15 ?m from the radiation-side reflection film.

Abstract: When manufacturing semiconductor elements, a group of semiconductor elements having a diffraction grating formed partly on the side of the facet from which laser light is emitted is formed collectively on a semiconductor wafer by using semiconductor process technologies. The semiconductor laser elements are arranged such that the light emitting facets are opposite to each other to thereby form each diffraction grating of the semiconductor laser elements arranged opposite to each other as one diffraction grating, cleaving this diffraction grating at respective cleavage planes to cut out laser bars, followed by the cleavage of cleavage planes to cut out semiconductor laser elements.

Abstract: A diffraction grating is provided in the vicinity of a GRIN-SCH-MQW active layer formed between a radiation side reflection coating provided on a radiation end face of a laser beam and a reflection coating provided on a reflection end face of the laser beam, and on the radiation side reflection coating side. An n-InP layer which covers the upper part of the diffraction grating is also provided, so that the current from the p-side electrode is prevented from being injected to the vicinity of the diffraction grating by the n-InP layer. An n-InPGaAsP diffusion prevention layer forms a non-current injection area so as to suppress alloying with the p-side electrode.

Abstract: A semiconductor laser device which has a diffraction grating partially provided in the vicinity of an active layer formed between a radiation-side reflection film provided on a radiation-side end surface of a laser beam and a reflection film provided on a reflection-side end surface of the laser beam, and which outputs a laser beam having a desired oscillation longitudinal mode based on a wavelength selection characteristic of at least the diffraction grating. The diffraction grating is formed in isolation with an isolation distance of Ls=15 ?m from the radiation-side reflection film.

Abstract: Provided is a method of manufacturing a semiconductor laser element for collectively forming semiconductor laser elements having diffraction grating partially provided at least on the side of laser light emitting end surface or laser light reflection end surface side using a semiconductor process technique. The method comprises the step of performing electron beam exposure or ion beam exposure for drawing only on a diffraction grating region on which said diffraction grating is provided in correspondence with a pattern of said diffraction grating, and masking the diffraction grating region and exposing a region other than said diffraction grating region with light or X-rays.

Abstract: A diffraction grating is provided in the vicinity of a GRIN-SCH-MQW active layer formed between a radiation side reflection coating provided on a radiation end face of a laser beam and a reflection coating provided on a reflection end face of the laser beam, and on the radiation side reflection coating side. An n-InP layer which covers the upper part of the diffraction grating is also provided, so that the current from the p-side electrode is prevented from being injected to the vicinity of the diffraction grating by the n-InP layer. An n-InPGaAsP spreading prevention layer forms a non-current injection area so as to suppress alloying with the p-side electrode.

Abstract: An n-InP cladding layer, a GRIN-SCH-MQW active layer, a p-InP spacer layer, a p-InP cladding layer and a p-InGaAsP contact layer are sequentially laminated on an n-InP substrate, and an n-type electrode is disposed on a lower portion of the n-InP substrate. Also, a diffraction grating is disposed on a portion region of the p-InP spacer layer, and an insulating film is disposed on the p-InGaAsP contact layer corresponding to the diffraction grating so that injected current is prevented from flowing in respect to the diffraction grating.

Abstract: Provided is a etch mask that prevents the separation of the etch mask which occurs in the vicinity of an end portion of a material to be etched during etching step. The etch mask is one formed on a surface of a material to be etched and comprising collected linear masks. A portion of a linear mask positioned in the vicinity of an end portion of the material to be etched becomes a wider portion as compared with the remaining portion or a zigzag portion. As required, the middle portion of the linear mask also becomes a wider portion or a zigzag portion.

Abstract: When manufacturing semiconductor elements, a group of semiconductor elements having a diffraction grating formed partly on the side of the facet from which laser light is emitted is formed collectively on a semiconductor wafer by using semiconductor process technologies. The semiconductor laser elements are arranged such that the light emitting facets are opposite to each other to thereby form each diffraction grating of the semiconductor laser elements arranged opposite to each other as one diffraction grating, cleaving this diffraction grating at respective cleavage planes to cut out laser bars, followed by the cleavage of cleavage planes to cut out semiconductor laser elements.

Abstract: Provided is a method of manufacturing a semiconductor laser element for collectively forming semiconductor laser elements having diffraction grating partially provided at least on the side of laser light emitting end surface or laser light reflection end surface side using a semiconductor process technique. The method comprises the step of performing electron beam exposure or ion beam exposure for drawing only on a diffraction grating region on which said diffraction grating is provided in correspondence with a pattern of said diffraction grating, and masking the diffraction grating region and exposing a region other than said diffraction grating region with light or X-rays.

Abstract: A semiconductor laser device with an active layer having a multi-quantum well structure including more than one well layer and more than one barrier layer and having a cavity length of more than 800 &mgr;m is disclosed, wherein the active layer includes a doped region which includes at least one well layer and at least one barrier layer adjacent to the well layer. The entire active region, comprising all of the well and active layers may be doped. Adjacent to the active layer are upper and lower optical confinement layers falls having a thickness within a range of from about 20 to about 50 nm. A optical fiber amplifier incorporating the semiconductor laser is also disclosed, including the semiconductor laser device sealed within a package disposed over a cooler, and wherein a light incidence facet of an optical fiber is optically coupled to the optical output power facet of the semiconductor laser device.